Set property to a config value via an Attribute

[KKSzymanowski]

Ability to set a property of an object to some config value when the object is constructed by the Container. API would look something like this:

class FooController extends Controller
{
    #[Config('app.url')]
    protected $appUrl;

    #[Config('foo.bar', 'some default value')]
    protected $fooBar;
}

Proof of concept:

1. Create a Config attribute:

   #[Attribute(Attribute::TARGET_PROPERTY)]
   class Config {
   public function __construct($key, $default = null)
   {
   
   }
   }

2. Change the last line in Illuminate\Container\Container::build()

   - return $reflector->newInstanceArgs($instances);
   + $object = $reflector->newInstanceArgs($instances);
   + 
   + foreach($reflector->getProperties() as $property) {
   +     foreach($property->getAttributes() as $attribute) {
   +         if($attribute->getName() == Config::class) {
   +             $property->setAccessible(true);
   +             $property->setValue($object, call_user_func_array('config', $attribute->getArguments()));
   +         }
   +     }
   + }
   + 
   + return $object;

3. Use the Attribute in a controller and see that the property value has been set to a value from app configuration.

What do you think?

[KKSzymanowski]

@taylorotwell Can I get your opinion about this?